The present invention relates to an improved tamping machine, particularly for regenerating railroad ballasts.
Trailer or self-propelled railcars, bearing groups of tamping machines arranged inside and outside each rail according to patterns known to the technician in the field and termed single- or twin-head, are usually employed to regenerate railroad ballasts. Each tamping machine generally has two pairs of vibrating hammers which are sunk into the ballast on one side and on the other of each tie to move the rubble constituting the ballast and tamp said tie with it.
In order to vibrate the hammers and sink them into the rubble, currently known tamping machines use mechanical systems essentially of the eccentric-mass or crank type. Such mechanical systems have many disadvantages, and chiefly: a considerable structural complexity arising from the high stresses transmitted to the various elements of the machine and the need to keep the vibration frequency of the hammers within relatively modest limits, both to contain the above mentioned stresses within acceptable limits and to limit power consumption.
In known machines, the vibration is furthermore simultaneously transmitted to all the pairs of hammers of each "head", where the term "head" indicates the set of elements acting on each tie.
This circumstance constitutes a considerable disadvantage, as it forces the outfitting of two different types of railcar, respectively for line work and for switch work. The first is of the twin-head type and can operate simultaneously on two ties, while the second necessarily has a single head and therefore its use for line work has an unacceptable performance, thus requiring the outfitting of differentiated railcars respectively for lines and switches.